Does a gas heater always have a pilot light?

Gas heaters that do not have pilot lights have electronic ignition systems instead. Newer gas furnaces with annual fuel utilization efficiency ratings higher than 80 use electronic ignitions featuring a hot-surface system or an intermittent pilot.

Modern electronic ignition furnaces have fewer problems than the older standing-pilot systems; however, the increased sophistication of this type of system limits what the do-it-yourself homeowner can do when it is time to troubleshoot the furnace's operation. While a pilot light features a small flame that is constantly burning, the intermittent pilot system works with a high-voltage spark to turn on the gas pilot and the primary burners, while hot-surface ignition uses a heating element similar to a light bulb filament to light the gas burner.